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2 years ago

Some water released 7800 J of energy when cooled from 78°C to 33°C. What was the mass of the water?

Chemistry

1 answer:

Karo-lina-s [1.5K]2 years ago

4 0

Answer:

-41. 47

Explanation:

m = q / Cp x T

m = Mass

q = Energy (or joules)

Cp = Heat Capacity

T = Change in Temperature

Water's heat capacity is always 4.18.

This is the formula you'll need for change in temperature:

Final - Initial

So, 33 - 78 = -45

m = 7800 / 4.18 x -45

= -41.47

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Corrections here: 1. When calcium reacts with water, the temperature changes from 18c to 39c

Ugo [173]

When calcium reacts with water, the temperature changes from 18c to 39c is an exothermic reaction as energy is releasing and increasing the temperature.

<h3>What is an exothermic reaction?</h3>

Exothermic reaction are those reactions in which energy is released when a reaction completes.

An example is burning of wood.

Thus, when calcium reacts with water, the temperature changes from 18c to 39c is an exothermic reaction as energy is releasing and increasing the temperature.

Learn more about exothermic reaction

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1 year ago

You have at your disposal 3 1-pound bags of various pure salts that dissolve readily in water. You can add one of the bags to a

Sedaia [141]

Answer:

This question appears incomplete

Explanation:

However, it should be noted that addition of soluble salts generally lowers the freezing point of water hence after the addition, water will no longer freeze at 0°C but lower.

Soluble salts tend to form more ions in water, it is these ions that are responsible for interfering with the hydrogen bonds hence lowering the freezing. Thus, (since each bag are of the same weight) <u>the bag that contains the salt that ionizes more in water will lower the freezing point by the greatest amount</u>.

NOTE: Different weight of the salts could lead to more ions been formed in the water by some salts as against the other.

6 0

3 years ago

Dalton's law of partial pressures states that the total pressure exerted by a mixture of gases is the sum of the pressures exert

Damm [24]

Answer: The given statement is true.

Explanation:

According to the Dalton's law, total pressure of a mixture of gases that do not react with each other is equal to the partial pressure exerted by each gas.

The relationship is as follows.

$p_{total} = \sum_{i=1}^{n} p_{i}$

or, $p_{total} = p_{1} + p_{2} + p_{3} + p_{4} + ......... + p_{n}$

where, $p_{1}, p_{2}, p_{3}$ ....... = partial pressure of individual gases present in the mixture

Also, relation between partial pressure and mole fraction is as follows.

$p_{i} = p_{total} \times x_{i}$

where, $x_{i}$ = mole fraction

Thus, we can conclude that the statement Dalton's law of partial pressures states that the total pressure exerted by a mixture of gases is the sum of the pressures exerted independently by each gas in the mixture, is true.

5 0

3 years ago

It says draw a ring around all the objects that will be attracted to a magnet the one there are : a 2p coin,cobalt,an aluminium

Katen [24]

Answer: do

Explanation:

5 0

2 years ago

A 59.1g sample of aluminum is put into a calorimeter (see sketch at right) that contains 250.0g of water. The aluminum sample st

Rainbow [258]

Answer:

The specific heat capacity of aluminum according to this experiment is 0.863 J/g°C

Explanation:

Step 1: Data given

Mass of aluminium = 59.1 grams

Mass of water = 250.0 grams

Initial temperature of aluminium = 91.3 °C

Initial temperature of water = 16.0 °C

Final temperature = 19.5 °C

Pressure remains constant

Specific heat capacity of water = 4.186 J/g°C

Step 2: Calculate specific heat of aluminium

Heat lost = heat gained

Qlost = -Q heat

Q = m*c*ΔT

heat aluminium = - heat water

m(aluminium) * c(aluminium) * ΔT(aluminium) = -m(water) * c(water) * ΔT(water)

⇒m(aluminium) = mass of aluminium = 59.1 grams

⇒c(aluminium) = the specific heat of aluminium = TO BE DETERMINED

⇒ΔT = the change in temperature = T2 -T2 = 19.5 - 91.3 = -71.8 °C

⇒ m(water) = 250.0 grams

⇒c(water) = the specific heat of water = 4.186 J/g°C

⇒ΔT = the change in temperature = T2 -T2 = 19.5 - 16.0 = 3.5 °C

59.1 * c(aluminium) * -71.8 °C = 250.0 * 4.186 J/g°C * 3.5 °C

c(aluminium) = 0.863 J/g°C

The specific heat capacity of aluminum according to this experiment is 0.863 J/g°C

3 0

2 years ago